CVE-2026-91981

Vikunja before 2.6.0 User Enumeration via v2 API

MEDIUM
4.3
CVSS Score
Published: September 15, 2026 at 03:18 PM UTC
Updated: September 21, 2026 at 07:17 PM UTC
1 product affected across 1 vendorVikunja

Using vikunja by go-vikunja?

Get instant alerts when new vulnerabilities affect vikunja - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM4.3
Exploit prediction
EPSS 0.3%
SSVC
PoC

Description

Vikunja versions before 2.6.0 fail to properly validate link-share tokens in the v2 API user search endpoints. Attackers with a read-only share link can enumerate project users via the projects endpoint and confirm arbitrary usernames exist via the global search endpoint.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 2.6.0
Vendor states this is fixed in 2.6.0 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.3MEDIUMVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-200

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card